Design of RoomTemperature THz and Infrared Sensing Devices Using Non-Toxic, Supply-Chain Secure Material Platform

Infrared sensing sits at an inflection point. The industry-standard HgCdTe (MCT) requires bulky cryogenic cooling and is built on toxic, supply-chain-fragile elements, while uncooled microbolometers, are limited to millisecond response times. This leaves unaddressed the regime of fast, uncooled, low-SWaP-C (Size, Weight, Power, and Cost) detection from the long-wave infrared (LWIR) through the THz, which hypersonic threat warning, proliferated drone platforms, and contested-spectrum operations now demand. Recently, new mechanisms have emerged that can fill this important technical gap. Oxychalcogenide films containing heavy elements have characteristic responses in the THz range [1-3] and can enable ms-scale detection responses in the THz and far-infrared spectral regions, e.g., hot-electron rectification/photothermoelectrics, thermally decoupled from the lattice of heavy elements [4-6]. Notably, these phenomena do not require cryogenic cooling like the MCT system because the signal is not based on an inter-band transition, and its response is orders of magnitude faster than that of room-temperature bolometers because it is driven by hot electrons decoupled from the lattice. Moreover, these materials, such as Bi2O2Se and InBiSe3, are composed of non-toxic, earth-abundant elements, and are supply-chain-secure material platforms. Department of War’s investments through the Multidisciplinary University Research Initiative (MURI) have already enabled the development of high-mobility chalcogenide films and their characterization via optical and THz spectroscopy [1–3]. Building on this, oxychalcogenide films can serve as room-temperature detectors offering uncooled, chip-scale access to the jam-free THz and far-infrared bands — a regime current sensor technologies cannot reach without cryogenic cooling — and will directly advance Quantum and Battlefield Information Dominance. Moreover, the hot-electron mechanism is fast, which allows detection of ms transients such as laser pulses and hypersonic signatures that slow uncooled microbolometers wash out.